JPH0139987B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing china clay, and in particular to a method for producing china clay with excellent properties such as plasticity in large quantities at low cost using china stone as a raw material. Since ancient times, high-quality porcelain with a white background called Arita ware has been produced in large quantities in areas centered on Arita City and Imari City, Saga Prefecture. Pottery clay is mainly used for making such porcelain, and traditionally, this clay is produced by crushing pottery stone with a dry stamper, elutriating it, and collecting the fine particles. Manufactured. By the way, this dry stamper is a machine that has been traditionally used since the Edo period, and the potter's clay obtained with this method is said to have excellent plasticity, and is still used today as the highest quality potter's clay. However, in terms of productivity, there was a problem in that the resulting china clay was expensive because it was produced in small quantities and consumed a lot of labor. Since the processing capacity of dry stampers is very small, they are not suitable for mass production of china clay.Therefore, in order to increase the throughput (the production amount of china clay), it is necessary to increase the number of stampers installed, and large installations are required. This is because the area is required. Furthermore, it is necessary to supply and take out raw stone (pottery stone) to and from each stamper, which requires a great deal of labor. For this reason, various types of pulverizers have been examined to replace such dry stampers, and as long as the type of pulverizer is selected, it has become possible to produce china clay in large quantities and at low cost. The china clay thus obtained is significantly inferior to conventional dry-stamped products in terms of performance such as plasticity, and the reality is that it has not yet been fully put to practical use. The present invention has been made against this background, and its purpose is to provide an effective method for mass-producing china clay with excellent properties such as plasticity at low cost. In order to achieve this object, the present invention provides a method for crushing pottery stone using a crusher.
3-25% of particles are 30μ or more and 44μ or more
Grind to 10% or less, then 25~
After classifying with a particle size of 44μ and collecting the material under the sieve, the obtained primary classification under the sieve is further classified into a secondary classification with a particle size of 10 to 18μ, and the obtained secondary classification under the sieve is It is characterized in that it is pulverized so that 40% or more of the particles have a particle size of 3μ or less, and the sieved particles obtained from the previous secondary classification are mixed with this. The pottery stone that provides good quality pottery clay according to the method of the present invention is a rock of the Muscovite group minerals-kaolin group minerals-quartzite system, and is composed of quartz, sericite, and/or kaolinite. Often, it may also contain pyrophyllite. Typical examples of such pottery stone include various kinds of pottery stones named after their production areas, such as Izumiyama pottery stone and Amakusa pottery stone, but in addition to Kumamoto prefecture and Saga prefecture, there are also other pottery stones such as Nagasaki prefecture, Gifu prefecture, and Ishikawa prefecture. It is widely distributed in Fukushima Prefecture, Fukushima Prefecture, etc., and overseas as well as China and South Korea. In the present invention, after mining such pottery stone, first of all, in order to supply it to the next crusher, for example,
It is crushed into particles with a maximum particle size of about 10 mm or less using a crusher or the like. Next, this coarsely crushed pottery stone with a certain particle size or less is crushed using a suitable crusher such as a roller mill or dry ball mill to reduce the proportion of particles of 30μ or more to 3 to 25%.
In addition, it is pulverized so that particles of 44μ or more are 10% or less. By selectively crushing the clay to achieve such a particle size distribution, the clay components (sericite, kaolinite, etc.) that make up the pottery clay can be effectively collected while suppressing the contamination of quartz components. . In other words, when the number of particles exceeding 44μ increases, the yield of clay becomes poor because these particles also contain clay, and when the number of particles less than 30μ increases, the quartz content in the pottery stone decreases. It becomes a fine powder, which makes it difficult to separate it from the clay component, which ultimately has a negative impact on the performance of potter's clay, such as its plasticity. However, while sericite and kaolinite grains are usually less than a few microns in size, the grain size of quartz varies depending on the source rock, but is much larger than sericite grains, and therefore it This is because if the pulverization is done all at once, even the quartz grains will be pulverized into fine particles, and even if classification is performed afterwards, the accuracy of separating the parts with a high clay content from the parts with a high quartz content will be very poor. The fraction must be kept within the above range so as not to cause too much grinding. In particular, in the present invention, as a pulverizer that provides such a particle size and is less prone to over-pulverization, pulverization is carried out using the centrifugal force of rotating rollers.
A so-called roller mill is recommended. In addition, as a crusher that provides such a particle size, there are a normal crusher that only performs a crushing operation, a crusher that has a built-in classification mechanism, and a crusher that is combined with a classifier. Although there are wet type ones, any type of pulverizer can be used as long as a pulverized product having a particle size distribution according to the present invention can be obtained. The pulverized ceramic stone thus selectively pulverized is then classified (primary classification) to a predetermined particle size between 25 and 44 μm using a dry or wet classifier, such as air elutriation or water elutriation. Within this range of 25 to 44μ, by selecting and classifying the particle size that allows the most efficient separation according to the size of the quartz particles in the original rock (pottery stone), the particles on the sieve (classified particles) are classified. Quartz is concentrated in the particles (larger than the particle size), while clay is concentrated in the particles below the sieve (particles smaller than the classified particle size).
In the present invention, the material under the sieve with a high clay content is collected and subjected to the next secondary classification. In other words, in the secondary classification (re-classification), the unsieved material obtained in the above-mentioned primary classification is classified into a predetermined particle size of 10 to 18μ using a dry or wet classifier (elutriation, water elutriation). It is done. Next, the unsieved particles obtained by this secondary classification (particles smaller than the classified particle size) are processed using a dry or wet pulverizer, for example, so that at least 40% of the particles are 3μ or less. After further pulverization using a vibrating mill etc.
The finely pulverized material is mixed with the sieved particles (particles larger than the classified particle size) obtained by the secondary classification, thereby obtaining the desired china clay. By going through such a specific secondary classification operation, a specific partial pulverization operation, and a remixing process, the final particle size distribution of the clay is effectively adjusted, and the following The clay is then finished with excellent properties such as plasticity. In addition, the mixture (pottery clay) obtained by mixing the finely pulverized secondary classification under the sieve and the secondary classification on the sieve as described above is dehydrated (in the case of wet mixing). It can be used as a product as it is, or it can be mixed with other clays, silica, feldspar powder, etc. and used as potter's clay or porcelain clay. Therefore, according to the present invention, a highly productive pulverizer can be used, thereby making it possible to produce high-quality plastic clay in large quantities at low cost. The area required was also reduced. By the way,
When a roller mill is used as a crusher, the production volume is approximately 40 times that of a conventional stamper mill if the installation area is the same, and even when a ball mill is used, the production volume is approximately 10 times that of a conventional stamper mill. It is possible to list the following. Furthermore, the yield of china clay from raw stone is 78-83% with roller mills and 75-78% with ball mills. Below, a few examples will be shown to clarify the present invention more specifically, but it goes without saying that the present invention is not limited in any way by the description of these examples. . In addition,
All percentages in the examples are by weight unless otherwise specified. Example 1 500 kg of Uchiyama pottery stone (produced in the Shimoda Kita Uchiyama area, Amakusa-cho, Amakusa-gun, Chomoto Prefecture), with a size of 1 cm square or less, was placed in a roller mill (manufactured by Ishii Grinding Machinery Works). While supplying sequentially, 6 particles of 37μ or more
Roller mill pulverization was performed under conditions such that the The obtained pulverized product contained 23% of particles with a size of 30μ or more and 5% of particles with a size of 44μ or more. Next, the pulverizer was classified using an elutriation classifier (Microplex manufactured by Yaskawa Electric Manufacturing Co., Ltd.).
The following were separated and collected. This separated collection material (the material under the primary classification sieve) is designated as sample A. And this
Re-classifying the classified matter of 37μ or less at 15μ (secondary classification)
It was divided into 35% of 37-15μ (on the sieve) and 65% of 15μ or less (under the sieve). Furthermore, the thus obtained particles of 15μ or less were crushed in a wet vibration mill (inner volume 60, cobblestones 10mm, alumina balls 100Kg, slurry concentration 45%) for 3 hours, so that 60% of the particles were 3μ or less. A finely ground product was obtained. Next, this finely ground material of 15 μm or less and the 37 to 15 μm material on the sieve obtained by the secondary classification are wet-mixed, dehydrated, and made into clay to obtain the desired china clay (Sample B). I got it. The yield from raw stone was 80%. Comparative Example 1 The Uchiyama pottery stone used in Example 1 above, with a size of 4 mm square or less, was put into a conventional stamper mill at 200 kg per mortar and crushed for 12 hours.
By elutriation, clay of 37 μm or less was collected, and the same clay as before (Sample C) was obtained. The elutriation yield was 45%. Example 2 Using pottery stone from Isai (produced in Isai district, Kamioka-cho, Yoshiki-gun, Gifu Prefecture) with a size of 1 cm square or less (crushed material), 300 kg of it was fed to a roller mill similar to Example 1, Roller milling was performed under conditions such that particles with a size of 35μ or more were 8%. The obtained pulverized material contains 20% particles of 30μ or more and 4% of particles of 44μ or more.
%. Next, the pulverized material was classified using an elutriation classifier similar to that in Example 1, and after collecting 35μ or less, the collected material was further classified by 15μ, and 35 to 15μ
It was divided into 30% and 70%. When this re-classified product of 15 μm or less was pulverized in a wet vibration mill under the same conditions as in Example 1, a pulverized product was obtained in which 57% of the particles were 3 μm or less. After wet-mixing the 35 to 15 micron particles separated in the previous re-classification into the finely ground product obtained in this way,
The clay was dehydrated and made into clay to obtain the target china clay (Sample D) according to the present invention. Example 3 20 kg of crushed Orinosako pottery stone (produced in the Shimoda Kita-Onosako area, Amakusa-cho, Amakusa-gun, Momoto Prefecture) with a diameter of 5 mm and 20 kg of cobblestones with a diameter of 2 to 5 cm were supplied to a ball mill with an internal volume of 60. By dry grinding for 8 hours,
A pulverized product was obtained in which 24% of the particles were 30μ or more, and 10% were 44μ or more. Next, this crushed material was classified by elutriation, and 40μ
After separating and collecting the particles below (under the sieve) (this collection is referred to as sample E), the particles below 40μ are further elutriated and reclassified using 15μ, and 35% of the particles are 40 to 15μ.
65% of the particles were separated from those with a diameter of 15μ or less. Then, by further pulverizing such particles of 15μ or less using a vibrating mill similar to those in Examples 1 and 2, a finely pulverized product in which 50% of the particles were 3μ or less was obtained, and this finely pulverized product and the separated into
The desired china clay (Sample F) was obtained by wet mixing the clay with a particle size of 40 to 15μ, dewatering, and making clay. -Performance test- Chemical composition and cumulative particle size distribution (by hydrometer method) of samples A to F obtained in the above examples and comparative examples
The results are shown in Tables 1 and 2, respectively. As is clear from these tables, china clays B, D, and F obtained according to the present invention have a lower SiO ₂ component, but a lower Al ₂ O ₃ component, and a K ₂ O component, compared to each raw stone. is increasing. It will also be appreciated that the particle size distribution of the china clay obtained according to the present invention is dominated by small particle size regions, such as stamper mill products.

【table】

[Table] In addition, cast molding and roller machine molding were performed using Samples A to F, and the molding characteristics of each were evaluated, and the results are shown in Table 3. In addition, the slurry concentration (%; 100
x solid dry powder/slurry) to approximately 66% (contains 0.22% of water glass as a peptizer based on the amount of solid dry powder), and cast 1000ml of this slurry using a plaster mold. It was implemented by In addition, demoldability in this case refers to the ability to pour a certain amount of slurry into a plaster mold, apply it to the surface of the mold, remove the remaining slurry, and then separate the plaster mold from the plaster mold. Semi-finishability refers to the quality of the finish when the excess portion of the demolded base material is cut off with a thin iron wire. In addition, roller machine molding is performed by molding a plate with a diameter of 100 mm and a height of 15 mm using a roller machine manufactured by Nippon Toki Co., Ltd. The moldability refers to the finish of the base material during roller machine molding. In addition, the occurrence of breaks after molding refers to the presence or absence of breaks (cracks) in the base material after roller machine molding. As is clear from the results in Table 3, samples B, D, and F according to the present invention were all recognized to have excellent molding properties, and were found to have excellent plasticity similar to dry stamper product C. confirmed.

【table】

Claims (1)

[Claims] 1 After coarsely crushing the pottery stone, it is crushed in a crusher so that the particles of 30 μ or more are 3 to 25% and the particles of 44 μ or more are 10% or less, and then classified to a particle size of 25 to 44 μ and sieved. After collecting the materials below, the obtained primary fraction under the sieve is subjected to secondary classification with a particle size of 10 to 18μ, and the obtained secondary classification under the sieve is divided into particles with a particle size of 3μ or less. A method for producing china clay, which is characterized by finely pulverizing the clay to a content of 40% or more, and mixing it with the sieved material obtained from the previous secondary classification.